Optionally allow empty junit test results

Change-Id: Ic0f8f939e32bdbc2bf264e0386cb97489877aacb
diff --git a/jjb/defaults.yaml b/jjb/defaults.yaml
index cc7c685..f7770bb 100644
--- a/jjb/defaults.yaml
+++ b/jjb/defaults.yaml
@@ -128,3 +128,7 @@
 
     # siab helm-charts
     siab-projects-regexp: '^(xos-core/.*|xos-profiles/seba-services/.*|xos-profiles/base-kubernetes/.*|workflows/att-workflow/.*|voltha/.*|onos/.*)$'
+
+    # Optionally allow JUnit results to be empty when test framework is set up,
+    # but no tests exist. Default behavior is to fail when test results are empty.
+    junit-allow-empty-results: false